Cervical dilator

ABSTRACT

A cervical dilator comprising a fluidtight bag formed from a flexible material and insertable in a collapsed state into the cervical canal, inlet means in said bag for periodically introducing fluid under pressure to alternately inflate said bag whereby the wall of said bag radially expands to directly contact the walls of said canal and to deflate said bag so as to cause dilatation of the cervix and simulate effects of labor contraction, a portion of the wall of said bag intermediate the ends thereof being adapted to be more resistant to radial expansion whereby to form on inflation of said bag a constricted waist portion which accommodates the edges of the cervix.

United States Patent Inventor Wallace 8. Shute 340 McLeod St., Ottawa,Ontario, Canada Appl. No. 793,369 Filed Jan. 23, 1969 Patented Dec. 14,1971 CERVICAL DILATOR 2 Claims, 2 Drawing Figs.

U.S. Cl 128/344, 128/361 Int. Cl ..A6lm 29/00,

A6 1 b 17/42 Field of Search 128/344, 349 B, 361; 206/D1G. 30

References Cited UNITED STATES PATENTS 9/1952 Edwards l28/349BUX YPrimary Examiner-Channing L. Pace AnorneyCushman, Darby & CushmanABSTRACT: A cervical dilator comprising a fluidtight bag formed from aflexible material and insertable in a collapsed state into the cervicalcanal, inlet means in said bag for periodically introducing fluid underpressure to alternately inflate said bag whereby the wall of said bagradially expands to directly contact the walls of said canal and todeflate said bag so as to cause dilatation of the cervix and simulateeffects of labor contraction, a portion of the wall of said bagintermediate the ends thereof being adapted to be more resistant toradial expansion whereby to form on inflation of said bag a constrictedwaist portion which accommodates the edges of the cervix.

CERVICAL DILATOR The present invention relates to a cervical dilatorwhich is adapted to be inserted into the cervical canal and to causeupon inflation and deflation thereof dilation of the cervix so as tosimulate the effect of labor contractions and thus hasten the processesof nature.

During labor, the cervix uteri dilates equally in all directions from adiameter of to centimeters under the pressure of intermittent uterinecontractions transmitted through the presenting part (head, breechand/or forebag of water). This dilation permits passage of the baby fromthe uterine cavity through the pelvis to delivery. Nature however doesnot produce such labor pains in any regular or standard pattern, sincethe anatomical and physiological characteristics of all women vary, thuslabor can be remarkedly eflicient and short or with noneffectivecontractions extremely protracted. The present invention provides asimple and relatively inexpensive device which will reproduce theeffects of labor pains more efficiently and accurately regulating thedilation of the cervix from 0 to 10 centimeters with safety thushastening the first stage of labor.

ln my Canadian application No. 958,955 I have disclosed and claimed sucha cervical dilator which comprises a fluidtight container formed from aflexible material and insertable in a collapsed state into the cervicalcanal, inlet means in said container for intennittently introducingfluid under pressure to alternately inflate said container such that aperipheral radial wall of said container expands radially to directlycontact the walls of said canal and deflate said bag so as to causedilatation of the cervix and simulate the effects of labor contractions,the ends of the container being adapted to limit axial expansion of saidcontainer during inflation. in particular, in my copending Canadianapplication the ends of the container are adapted to substantiallyprevent axial expansion of the container on inflation thereof,essentially all the expansion of the container during the dilatationbeing in a radial direction as axial expansion of the container causesexpansion of the container into the uterus of the pregnant women,thereby hindering to a substantial extent the delivery of the baby whichis undesirable.

Further, the container has a waist portion intermediate the ends thereofand particularly equidistant from the ends thereof which waist portionis of reduced radial dimension for the location of the edges of acervical os. This allows for the proper positioning of the cervicaldilator in the cervical canal when used in simulating the effects oflabor contraction.

It has now been found according to the present invention that byadapting the waist portion intermediate the ends of the container or bagso as to be more resistant to radial expansion than the remainder of thewalls of the bag, on inflation of the bag the waist portion isconstricted and thus at all times accommodates the edges of the cervical0s and prevents the bag when under inflation from moving axially into orout of the uterus which is undesirable and thus allows only radialexpansion and contraction of the walls of the bag' to take place.

According to the present invention therefore there is provided acervical dilator comprising a fluidtight bag formed from a flexiblematerial and insertable in a collapsed state into the cervical canal,inlet means in said bag for periodically introducing fluid underpressure to alternately inflate said bag whereby the wall of said bagradially expands to directly contact the walls of said canal and deflatesaid bag so as to cause dilatation of the cervix and simulate effects oflabor contraction, a portion of the wall of said bag intermediate theends thereof being adapted to be more resistant to radial expansionthereby to form on inflation of said bag a constricted waist portionwhich accommodates the edges of the cervix.

The bag which is suitable made of a relatively heavy gauge plasticmaterial such as polyvinyl chloride suitably has embedded in the waistportion a relatively inextensible fiber such as cotton fiber whichprovides the necessary resistance to expansion of the waist portionwhich waist portion is suitably equidistant from the ends of the bag andthus on inflation of the bag the waist portion is constricted toaccommodate the edges of the cervix.

As with the cervical dilator of my Canadian application No. 958,955 theends of the bag are adapted to restrict axial expansion of the bagduring inflation and desirably the ends of the bag allow substantiallyno axial expansion of the bag on inflation thereof.

Inflation and deflation of the bag may suitably be effected byperiodically discharging fluid under pressure from a pressure means intosaid bag through the inlet means, the pressure means being suitably ahydraulic pressure means, the fluid being suitably water. Thus thepresent invention also provides in combination with the aforesaidcervical dilator of the present invention means for periodicallydischarging fluid under pressure into said bag through said inlet meansto effect inflation or deflation thereof.

The present invention will be further illustrated by way of theaccompanying drawings in which FIG. 1 is a perspective view of adeflated cervical dilator according to a preferred embodiment of thepresent invention, and

FIG. 2 is a similar view of the cervical dilator of FIG. 1 in theinflated state.

Referring to the accompanying drawings, the cervical dilator comprises abag 1 formed from a flexible plastic material such as polyvinyl chloridesealed along the top and bottom edges thereof so that there is noappreciable axial expansion of the bag on inflation thereof and havingan inlet 2 for the periodic introduction of water under pressure intothe bag 1 to effect radial inflation and deflation thereof. The bag Ihas a waist portion 3 which has a continuous thread 4 embedded thereinwhich restricts radial expansion of the waist portion 3 on inflation ofthe bag 1 (see HO. 2) thus providing accommodation for the edges of thecervix during expansion of the bag 1 and as such avoiding the tendencyof the bag I to move axially with respect to the cervix during inflationthereof.

I claim:

1. A cervical dilator comprising a flattenable, closed end, tubularfluidtight bag formed from a flexible plastic material and insertable ina collapsed state into the cervical canal, inlet and outlet means insaid bag for allowing intermittent introduction of fluid under pressureto alternately inflate said bag such that the peripheral tubularsidewall of said bag radially expands to directly contact the walls ofsaid canal and deflate said bag so as to cause dilatation of the cervixand simulate effects of labor contraction, a portion of the peripheralwall of said bag intermediate the ends thereof including relativelyinextensible reinforcing means which extend circumferentially of theperipheral wall in radially restraining engagement therewith so as tocause said portion of said peripheral wall to be more resistant toradial expansion than the remainder of said peripheral wall whereby toform on inflation of said bag a constricted waist portion havingsubstantially the same girth when said bag is inflated as when said bagis in said collapsed state and which locates and retains the edges ofthe cervix when said bag is inflated, the ends of said bag definingsubstantially the extremities of said dilator and being reinforced bybeing folded transversely and sealed to limit axial expansion of saidbag during inflation.

2. The cervical dilator of claim 1 wherein the bag peripheral wall isformed from polyvinyl chloride and relatively inextensible reinforcingmeans is a continuous textile thread imbedded in said portion of theperipheral wall.

i i l l

1. A cervical dilator comprising a flattenable, closed end, tubularfluidtight bag formed from a flexible plastic material and insertable ina collapsed state into the cervical canal, inlet and outlet means insaid bag for allowing intermittent introduction of fluid under pressureto alternately inflate said bag such that the peripheral tubularsidewall of said bag radially expands to directly contact the walls ofsaid canal and deflate said bag so as to cause dilatation of the cervixand simulate effects of labor contraction, a portion of the peripheralwall of said bag intermediate the ends thereof including relativelyinextensible reinforcing means which extend circumferentially of theperipheral wall in radially restraining engagement therewith so as tocause said portion of said peripheral wall to be more resistant toradial expansion than the remainder of said peripheral wall whereby toform on inflation of said bag a constricted waist portion havingsubstantially the same girth when said bag is inflated as when said bagis in said collapsed state and which locates and retains the edges ofthe cervix when said bag is inflated, the ends of said bag definingsubstantially the extremities of said dilator and being reinforced bybeing folded transversely and sealed to limit axial expansion of saidbag during inflation.
 2. The cervical dilator of claim 1 wherein the bagperipheral wall is formed from polyvinyl chloride and the relativelyinextensible reinforcing means is a continuous textile thread imbeddedin said portion of the peripheral wall.